Knurling tool for internal cylindrical surfaces



R. R. TEETOR Nov. 18, 1952 KNURLING TOOL FOR INTERNAL CYLINDRICALSURFACES Original Filed Nov. 18, 1946 h m. mt- 5 INVENTOR.

with the heat of the engine, the intimate contact therebetween ismaintained. Such intimate contact provides for a more rapid transfer ofheat from the sleeve to the cylinder block, thus improving the conditionunder which the sleeve operates. In the present instance, the metal isplaced under stress by outward deformation at closely spaced points,areas or lines throughout a band at the end of the sleeve. While suchdeformation of the metal may be attained by peening, spinning orrolling, knurling of the internal surface of the sleeve throughout thisband is preferred. The knurling is of sufficient depth to force themetal outwardly to form a slight bell at the end of the sleeve with thebelled portion firmly abutting the bore of the cylinder block to providethe intimate contact necessary to prevent seepage of oil therebetweenand to increase the rate of transfer of heat from the sleeve to thecylinder block. The knurling provides rounded points or ridges betweenthe grooves thereof, which conform to the inner diameter of the majorportion of the liner and places the metal throughout this area in astressed condition.

To illustrate the use for which a tool embodying the invention isadapted, I have shown in Figs. 1, 2 and 4 of the drawing a fragmentaryportion of a cylinder block casting It provided with a cylinder bore Hadapted to receive a sleeve 12. The sleeve I2 may extend throughout thelength of the cylinder bore l I so that the piston for the cylinder willoperate within the sleeve. The cylinder block casting, as is usual, isprovided with a flat end surface 13 against which a cylinder head isadapted to be secured by means of bolts extending into threaded holes isin the cylinder block casting. The sleeve l2, at its upper or combustionchamber end, is preferably rounded as at I? (see Fig. 4) to facilitateinsertion of a piston within the sleeve and is flush with the surface I3.

As illustrated in Fig. 4, an annular area or band I6 is to be knurled toa depth and with sufficient pressure to outwardly deform the metalwithin the band into close intimate contact with the bore l I. face ofthe sleeve resulting from the knurling preferably are aligned with theinner surface of the major portion of the sleeve so that the piston canbe inserted and withdrawn through the knurled end of the sleeve withoutinterference from the knurling. The knurlin may be of any desired type,that is, it may be formed by crossed grooves, resulting in pointsbetween the rooves, or it may be formed by grooves extending only in asingle direction to produce ridges therebetween. The principal feature,however, of the knurling is to force the metal outwardly into intimatecontact, as indicated at IT, with the bore H.

A tool embodying the invention provides a simple means for effectingsuch knurling. The tool herein illustrated is shown as hand operated,although it of course may be power operated, and is adapted to bereadily mounted on the cylinder block to perform the knurling operation.I its preferred form, the tool comprises a support in the nature of abridge member 20 spanning the end of the cylinder and provided with boltholes 2! adapted to be registered with the cylinder head bolt holes 14in the cylinder block casting. Bolts 22 are inserted through the holes2| in the bridge member 20 and are threaded into the holes M in theblock to rigidly secure thebridge member in place.

The points or ribs on the inner sur- The bridge member is provided witha central aperture 23 adapted to be aligned with the cylinder bore andto receive a bushing 24 therein, the aperture 23 and bushing 24 beingthreaded to provide adjustment axially of the cylinder. The bushing 24is formed with a head 25 at its upper end by which the bushing may berotated to adjust it within the bridge member 20, and a lock nut 26 ismounted on the bushing to rigidly lock it in place within the bridgemember after it has been adjusted. The bushing is provided with acentral bore 30 in which a spindle 3| is rotatably mounted. The spindle3|, at its lower end, is provided with a flange 32 while at its upperend a collar 33 is keyed thereto and secured by a setscrew 34. Thecollar 33 is hexagonal in form so that a wrench may be placed thereon torotate the spindle 3| within the bushing 24. Thrust washers 35 arepreferably interposed between the flange 32 and the bushing 24 andbetween the collar 33 and the head 25 of the bushing.

The spindle 3| is arranged to carry knurls adapted to be positionedwithin the upper end of the cylinder sleeve I 2 with the knurls arrangedso that they may be expanded outwardly to bear against the sleeve. Tothis end, a plate is mounted in spaced parallel relation to the flange32, the plate 40 being secured to the flange by means of rivets ll (seeFig. 3). Mounted between the flange 32 and the plate 3%] is a pluralityof rocker arms 62 pivotally supported by the plate and flange on axeseccentric to the axis of the spindle but symmetrically arranged relativeto the spindle.

Thus, each arm is pivotally carried by a pivot pin 43 mounted adjacentthe periphery of the flange 32 and plate 40. Each rocker arm isgenerally triangular in form with one corner thereof pivoted by the pin43 and another corner carrying a knurl 4 t rotatably supported in anotch in the rocker arm by a pin 45.

The rocker arms42 are adapted to be swung outwardly about their pivots43 to cause the knurls 44 to bear against the internal surface of thesleeve l2. To force the knurls outwardly, each rocker arm 42 is providedwith a tapered surface 43 at its third corner, adapted to cooperate witha tapered o-r conical nut 41 mounted concentrically with the spindle soas to 00- act with all of the rocker arms. To provide for insertion andmovement of the nut 41, the plate 40 has a central aperture 48. As willbe apparent by inspecting Fig. 3, the line of contact of the nut 41 witheach surface 46, the axis of the associated knurl 44, and its line ofcontact with sleeve I2 all lie substantially in the same axial plane.Thus, the pressure exerted by the nut 41 is directly aligned with knurlso that very little stress is placed on the pivot pins 43.

The nut 47 is adapted to be adjusted axially of the spindle to effectswinging movement of the rocker arms #2. To this end, the nut 41 isthreaded on a bolt 50 extending through the spindle 3l with the head ofthe bolt, indicated at 5|, located adjacent the collar 33. By turningthe bolt 50, the threaded engagement thereof with the nut 41 adjusts thenut axially of the spindle to move the rocker arm-s outwardly.

In using the tool heretofore described, the bridge member 20 is placedover the end of the cylinder with the bolts 22 threaded into the holesIt. The bolts 22 are not tightened down until the tool is properlycentered with relation to the to shift to a slight extent relative tothe bolts 22 by virtue of the fact that the bolt holes 2| through thebridge member 20 are somewhat larger than the diameter of the bolts.Such p0- sitioning of the bridge member 20 brings the rocker arms withtheir knurls in position to enter the end of the cylinder liner. Inorder to adjust the knurls longitudinally of the cylinder so that theywill act on the desired portion of the liner, the spindle may beadjusted axially by means of the bushing 24 and its threaded connectionwith the bridge member 20. After the bushing 24 has been adjusted to thepoint where the knurls are properly positioned, it is locked in place bymeans of the lock nut 26.

The bolt 59 is then turned to draw the nut 41 upwardly and swing therocker arms 42 outwardly to bring the knurls into bearing engagementwith the sleeve l2. Such outward movement of the knurls 44 will causethe tool to be centered with the cylinder sleeve, since the bridgemember may shift slightly relative to the bolts 22 before the latter aretightened. When the device is so centered, the bolts 22 are thentightened to rigidly clamp the bridge member 20 to the cylinder block.

The device is then ready for the knurling operation, which isaccomplished by turning the bolt 50 to draw the nut 41 upwardly and thuscause the knurls M to bear outwardly against the sleeve l2 withsufficient pressure to deform the metal of the sleeve. The spindle isthen rotated by placing a wrench on the collar 33 to roll the knurlsentirely around the circumference of the sleeve, the bolt 50 beingadjusted during the rotation of the spindle to achieve the desireddeformation of the metal of the sleeve. In this instance, the resultantridges formed by the knurling operation in the inner surface of thesleeve are held to the same diameter as the unknurled inner surface ofthe sleeve. As a result of this knurling operation, the metal of thesleeve is forced outwardly and placed under stress so that it has as-ufiiciently intimate contact with the bore of the cylinder to prevententrance of oil between the sleeve and the bore.

With the tool described above, positioning of the tool in centeredrelation with the cylinder is accomplished by the knurls themselves,which are thereafter forced outwardly by their adjusting means to effectthe knurling operation. Such operation can be readily performed by handsince the spindle 3| can easily be rotated to move the knurls about theinner periphery of the sleeve by placing a wrench on the collar 33.

I claim:

1. A tool for knurling an internal cylindrical surface within anarticle, comprising a bridge member adapted to span one end of saidsurface and to be secured to said article, a bushing threaded into saidbridge member and adapted to be positioned with its axis coincident withthat of the cylinder when the tool is set for operation, a spindlejournaled in and held against endwise movement relative to said bushingand adjustable axially by adjustment of the bushing in said bridgemember, said spindle having an axial bore and a flange at one end, aplurality of rocker arms pivotally connected to said flange for movementradially of said spindle and disposed symmetrically about the axis ofsaid spindle, a plurality of rotary knurls carried by the respectiverocker arms, a bolt extending through said spindle bore, and a conicalnut threaded on said bolt and engaging said rocker arms, said nut beingmovable axially of the spindle by rotation of said bolt and beingoperable when moved in one direction to swing said rocker arms outwardlyand thereby force said knurls into pressing engagement with saidsurface.

2. A tool for knurling an internal cylindrical surface, comprising asupporting member adapted to span one end of said surface and having anaperture adapted to be positioned with its axis coincident with that ofsaid surface, a spindle extending through said aperture and having anaxial bore, a plurality of knurl-supporting members movably carried bysaid spindle at one end thereof for movement radially of the spindle, aplurality of rotary knurls mounted on the respective knurl-supportingmembers, a threaded rod extending through said bore and having a headelement at one end and a nut element threaded on the other end, one ofsaid elements being conical in form and engaging said knurl-supportingmembers, the other of said elements engaging said spindle wherebyrotation of said other element will adjust said conical element axiallyto move said knurl-supporting members outwardly, and a bushing threadedin said aperture and holding said spindle against endwise movementrelative to the bushing, whereby the position of said knurls may beadjusted axially of said surface by rotation of said bushing.

3. A tool for knurling an internal cylindrical surface comprising arotatable spindle having an axial bore, a plurality of knurl-supportingmembers supported on one end of said spindle for movement radiallythereof, a plurality of rotary knurls carried by the respectiveknurl-supporting members, conical means located on the axis of saidspindle between said knurl-supporting members and adjustable axially ofthe spindle for moving the said knurl-supporting members outwardly,means extending axially through said bore for adjusting said conicalmeans, a support adapted to span one end of said surface and having anaperture adapted to be positioned coaxially with said surface, and abushing having said spindle secured therein against endwise movement butfreely r0- tatable therein, said bushing being threaded in said aperturewhereby said knurls may be adjusted axially of said surface.

RALPH R. TEETOR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 405,226 Schaubel June 11, 1889911,172 Stavenik Feb. 2, 1909 964,272 Kaiserman July 12, 1910 1,837,624Maupin Dec, 22, 1931 2,155,542 Graham Apr. 25, 1939 2,409,219 MaxwellOct. 15, 1946 FOREIGN PATENTS Number Country Date 12,341 Great BritainSept. 12, 1884 84,261 Sweden Sept. 3, 1935 555,237 Great Britain Aug.11, 1943

